Navigation systems are already known. In general, map data, including road data, acquired by digitizing each point on a road of a map, is stored in a storage device in advance. A map data group which covers a predetermined size of area including the current position of the vehicle is read from the storage device while detecting the current position and heading direction of the vehicle using various sensors. The map data group is then displayed on a screen of the display device as a map of the area around the current position of the vehicle. The vehicle mark is automatically displayed on the map to indicate the current position and heading direction of the vehicle.
Conventional navigation devices have a function to automatically set the route to the destination. When a route is set, one route is selected out of a plurality of route candidates based on computation considering various conditions, such as the presence of a toll road and the shortest distance, on the routes between the start point, the destination and transit locations, and the selected route is displayed on the map.
The navigation device disclosed in Japanese Patent Application Kokai (Laid-Open) No. 2003-269971 has a camera mounted on a vehicle. This camera captures the image in front of the vehicle when the vehicle approaches a guide point, such as a cross-section, on the route. The captured image is displayed on the display device.
If a driver can know the status of a guide point on a new route by image before the vehicle approaches this guide point, this helps the driver to drive comfortably. This is also comfortable to passengers in the vehicle. However, there are many guide points, such as cross-sections, and the status of the guide points often changes due to construction of the guide points and the peripheral areas. Thus, the conventional car navigation device must have a large storage capacity of an image. In other words, it is difficult, at low cost, to display the image of a guide point before the vehicle approaches the guide point.
Such a problem also exists in a navigation system for pedestrians, because the navigation system provides a pedestrian with the image of a point on a traveling road which the pedestrian is approaching.